A sniper is a person, who is most of the time a soldier or a law enforcement agent specialized in accuracy shots. Snipers generally use modified high-precision rifles. There are two types of snipers, and the difference relies on the the range of the shot and the penetration force of the weapon used. Snipers also have to be skilled in hiding, infiltration, and observation techniques.

In the army, the main mission of snipers is to do a detailed reconnaissance of an enemy position, and if needed, reduce enemy's defences by shooting at some key targets with the rifle.
The targets snipers have to kill in priority are officers or soldiers responsible for communication.
The sniper can watch out enemy bases, or mark a target for a bombing. In occidental armies the sniper is usually working with an observer who assists him and may substitute him if the sniper is tired.

Snipers can be used for police's missions as well. Policemen snipers don't have the same spots of action, the same tactic approaches, and the same trainings as the military snipers. Policemen snipers may be present during an event in order to watch out persons' security, and also may be called to eliminate a target in case of dangerous situation such as hostages taken by force.